Benzaldehyde amines with

Aldehydes undergo condensation with primary amines with the elimination of water to give compounds known as SchifF s Bases, which can also be used to characterise aldehydes. Benzaldehyde for example condenses readily with... 

Heat the amine with one or two mols of redistilled benzaldehyde (according as to whether the base is a monamine or diamine) to 100° for 10 minutes if the molecular weight is unknown, use 1 g. of the base and 1 or 2 g. of benzaldehyde. Sometimes a solvent, such as alcohol (5 ml.) or acetic acid, may be used. Recrystallise from alcohol, dilute alcohol or benzene. 

Dibenzjiamine, [103-49-17, CgH CH2NHCH2CgH (bp, 300°C at 101.3 kPa) is produced by reaction of benzyl amine with benzaldehyde and hydrogenation of the Schiffs base. It is used in mbber and tire compounding, as a corrosion inhibitor, and as an intermediate in the production of mbber compounds and pharmaceutical products. 

Further substitution of benzoic acid leads to a drug with antiemetic activity. Alkylation of the sodium salt of p-hydroxy-benzaldehyde (8) with 2-dimethylaminoethyl chloride affords the so-called basic ether (9). Reductive amination of the aldehyde in the presence of ammonia gives diamine, 10. Acylation of that product with 3,4,5-trimethoxybenzoyl chloride affords trimetho-benzamide (11). ... 

Use of the Knoevenagel reaction (67OR(l5)204), in which a benzaldehyde reacts with an activated methylene compound in the presence of an amine, goes some way to overcoming the inherent difficulties of the Perkin synthesis of coumarins (see later). In order to obtain the coumarin rather than the usual cinnamic acid, a 2-hydroxy substituent must be present... 

As illustrated by the examples in Table 3.9, resin-bound 4-alkoxybenzylamides often require higher concentrations of TFA and longer reaction times than carboxylic acids esterified to Wang resin. For this reason, the more acid-sensitive di- or (trialkoxy-benzyl)amines [208] are generally preferred as backbone amide linkers. The required resin-bound, secondary benzylamines can readily be prepared by reductive amination of resin-bound benzaldehydes (Section 10.1.4 and Figure 3.17 [209]) or by A-alkyla-tion of primary amines with resin-bound benzyl halides or sulfonates (Section 10.1.1.1). Sufficiently acidic amides can also be A-alkylated by resin-bound benzyl alcohols under Mitsunobu conditions (see, e.g., [210] attachment to Sasrin of Fmoc cycloserine, an O-alkyl hydroxamic acid). 

Heat the amine with 1 or 2 moles of redistilled benzaldehyde (according to whether the base is a monamine or diamine) to 100 °C for 10 minutes if the... 

Another class of substances of interest as bifunctional diazo components consists of special diamines that can be manufactured by the reaction of aromatic amines with benzaldehyde or cyclohexanone, e.g.,16 and 16a. 

Aldimines react with allyl bromide in the presence of metallic bismuth and tetrabutylammonium bromide in acetonitrile to give homoallyl amines (Equation (42)).77 When a chiral imine derived from benzaldehyde and (S)-valine methyl ester is used as the substrate, the allylation with allylic bismuth(m) species takes place smoothly by the assistance of a Lewis acid such as BF3-OEt2 and A1C13 to afford a chiral homoallylic amine with high diastereoselec-tivity (Equation (43)).78... 

Emerson and Waters alkylated primary aromatic amines with C2-C7 aliphatic aldehydes and benzaldehyde over Raney Ni in the presence of sodium acetate as a condensing agent and obtained /V-alkylanilincs in 47-65% yields.33 With C2-C5 aldehydes, up to 10% of the tertiary amines were produced, but no tertiary amines were found in the case of heptanal and benzaldehyde. With acetaldehyde in the absence of sodium acetate, aniline was recovered unchanged over platinum oxide and a mixture of amines resulted over Raney Ni, compared to 41 and 58% yields of N-ethylaniline over platinum oxide and Raney Ni (eq. 6.12), respectively, in the presence of sodium acetate. 

The synthesis of BENZYL ISOCYANIDE from benzaldehyde via reductive amination with 5-aminotetrazole followed by oxidation of the resultant amine with sodium hypobromite provides a general method for the synthesis of isocyanides. The preparation of BIS(2,2,2-TRICHLOROETHYL) AZODICARBOXYLATE makes available an alternative to dimethyl azodicarboxylate that is not only more reactive in Diels-Alder reactions but whose ester groups can be removed under neutral conditions. 

The use of a C-enriched building block anchored to a resin makes the gel-phase spectrum selective for the appearance of the new C signal, and the enrichment allows much shorter acquisition times (133, 134) a real-time kinetic was reported for the alkylation of amines with C-enriched bromoacetic acid (135). An example from our laboratories (136) shows the formation of a cyanohydrin on SP is monitored by C-enriched gel-phase NMR using C-benzaldehyde. The appearance of the cyanohydrin signal (63.2 ppm) and its increase at different reaction times is easily monitored by comparison with the constant signals of the solvent (deuterated benzene, 133-126 ppm. Fig. 1.19, spectra A-D). A major drawback of this technique is the cost and the limited availability of C-enriched building blocks, which currently severely limits its application. 

Acid Amides can be produced by acylating ammonia with esters, acid anhydrides, or the acids themselves (above 100 °C) an important product is formamide from methyl formate. Alternatively acid amides can be synthesized by reacting acid halides with ammonia. Catalytic hydrogenation converts the acid amides to primary amines. Ammonia and aldehydes or ketones are the basis for different stable products. With formaldehyde hexamethylenetetramine (urotropine) is obtained with acetaldehyde, ammono acetaldehyde with benzaldehyde, hydrobenzamide with ethylene and propylene oxides, aqueous ammonia reacts to form ethanol- or propanolamine. 

In addition to four component condensation, several other applications of chiral primary ferrocenylalkyl amines have been published. Thus, an asymmetric synthesis of alanine was developed (Fig. 4-3la), which forms an imine from 1-ferrocenylethyl amine and pyruvic acid, followed by catalytic reduction (Pd/C) to the amine. Cleavage of the auxiliary occurs readily by 2-mercaptoacetic acid, giving alanine in 61% ee and allowing for recycling of the chiral auxiliary from the sulfur derivative by the HgClj technique [165]. Enantioselective reduction of imines is not limited to pyruvic acid, but has recently also been applied to the imine with acetophenone, although the diastereoisomeric ferrocenylalkyl derivatives of phenylethylamine were obtained only in a ratio of about 2 1 (Fig. 4-31 b). The enantioselective addition of methyl lithium to the imine with benzaldehyde was of the same low selectivity [57]. Recycling of the chiral auxiliary was possible by treatment of the secondary amines with acetic acid/formaldehyde mixture that cleaved the phenylethylamine from the cation and substituted it for acetate. 

Formation of N—O bonds via amination with oxaziridines has been little studied. Benzaldehyde oxime 0-ethyl ether, along with other products, are obtained on treatment of 3-phenyloxaziridine (56 Me = H) with sodium ethoxide (67LA131,91S327). 

An ideal method for testing a wide variety of substructures was developed through the condensation of enantiomerically pure chiral primary amines with 2-(2-bromoethyl)benzaldehyde (11) as shown in Scheme 5.14 [19,21]. 

BENZENECARBINOL or BENZENECARBONAL (100-51-6) Forms explosive mixture with air (flash point 213°F/101 °C). Contact with water may cause frothing. Slowly oxidizes in air and oxygen, forming benzaldehyde. Incompatible with mineral acids, caustics, aliphatic amines, isocyanates. Reacts violently with strong oxidizers, and explosive with sulfuric acid at elevated temperature. Corrodes aluminum at high temperature. Attacks some nonfluorinated plastics may not attack polypropylene. 

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